Jacks of the type contemplated herein are used for the repair or replacement of automobile, truck or similar vehicle transmissions. The jack must have the capability of both raising and lowering the transmission for repair and replacement. Because of the various sizes and shapes of the transmissions, adjustments have to be made in order to accommodate these variations. However, due to the variety of shapes the transmissions are often mounted off center to the jack with respect to either the lateral or longitudinal relation of the transmission to the jack. This imparts a side load to the lifting mechanism of the jack which causes binding on the piston assemblies used to raise and lower the load and reduces the overall stability of the jack.